Investigation of Multiple X(H---Y Hydrogen Bonds (X=C,N;Y= Co, N, O) in the Molecular Aggregation of the Family of Salts [R₃NH]⁺[Co(CO)₃L]^-. Juan C. Mareque and Lee Brammer, Department of Chemistry, University of Missouri-St. Louis, 8001 Natural Bridge Road, St. Louis, MO 63121-4499, USA.

Our interest in hydrogen bonds with direct participation of a transition metal, primarily as hydrogen bond acceptor, led us to the systematic investigation of a family of salts of general formula [R₃NH]⁺ [Co(CO)₃L]^-(L=CO or Phosphine). This work allowed us to study the effect of changes both in the coordination sphere of the cobalt and in the properties of the amine on the overall strength of these `novel' hydrogen bonds. For the majority of the cases studied so far, the hydrogen bond N(H---Co has been the major intermolecular cohesive force in the molecular structure of these salts, but not always. We will present a case in which the dominant interaction between the cation (R₃NH⁺) and the anion (Co(CO)₄ ^-), is an N(H---O interaction. Here, the acceptor atoms are cobalt-bound terminal carbonyl oxygens of the anion rather than the cobalt atom. More recently we have also been investigating the role of hydrogen bonds, particularly those indirectly involving a metal center, in the supramolecular aggregation of organometallic systems. Here, we will discuss the C(H---O and N(H---N hydrogen bond patterns in the crystal structures of these [R₃NH]⁺[Co(CO)₃L]^- salts.